Sara R. Jones, PhD
Sara R. Jones, PhD - Research Interests
Our laboratory is mainly focused on measuring monoamine neurotransmitters in several different animal models of drug and alcohol abuse. The two primary techniques used are cyclic voltammetry and microdialysis. There are 4 major ongoing projects:
1) Binge/Abstinence Cocaine Self-Administration. We are attempting to understand alterations in the dopamine and serotonin systems that occur in response to binge/abstinence cocaine self-administration under several different schedules. We have already documented marked tolerance of the dopamine system to cocaine effects after binge-like self-administration which leads to escalation of cocaine intake. This project is in close collaboration with Dr. David C.S. Roberts’ laboratory, where the cocaine self-administration takes place.
Additional Projects: Circadian/Diurnal alterations in dopamine system function and cocaine self-administration; Long-lasting speedball (heroin+cocaine) effects on the dopamine system and cocaine self-administration.
People involved: Rodrigo Espana, PhD, Mark Ferris, PhD, Jason Locke, Joanne Konstantopoulos
2) Ethanol Effects on Monoamines. This topic includes several different projects.
A) Stress, Ethanol and Dopamine. We are examining the interactions between stress and ethanol exposure on dopamine and serotonin systems in mice. This project is part of the Integrative Neuroscience Initiative on Alcoholism (INIA) consortium funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). We expose mice of different genetic backgrounds (inbred strains, mutated and transgenic mice) to ethanol in a vapor chamber with or without stress occurring before the ethanol exposure. Then we look at dopamine using microdialysis and voltammetry to find out if the combination of stress and ethanol is different than either intervention alone.
B) Drinking Monkeys. Through the Center for the Neurobehavioral Study of Alcohol (CNSA), we have been able to collect brain tissue from monkeys that have been voluntarily drinking ethanol for more than a year to examine the dopamine system. The monkeys come from the laboratory of Drs. Allyson Bennett and David Friedman in our department.
C) Methylphenidate (Ritalin) and Ethanol. This is a collaboration with Dr. Jeff Weiner to examine the effects of chronic methylphenidate exposure during development on voluntary operant ethanol self-administration in rats. It appears that rats drink in a binge-like pattern and exhibit locomotor sensitization following methylphenidate. We will be using microdialysis and voltammetry to assess changes in the dopamine and serotonin systems of these rats.
People involved: Tiffany Mathews, Joanne Konstantopoulos, Jason Locke
3) Ritalin and the Serotonin Switch. We found that chronic blockade of the dopamine transporter through genetic deletion of the dopamine transporter (DAT KO mice) or chronic administration of methylphenidate (Ritalin) causes persistently elevated dopamine levels, there is a major change in the function of the serotonin system, especially in the ventral tegmental area, such that blockade of the serotonin transporter will cause an elevation in dopamine levels in the nucleus accumbens. There are implications for this finding in the drug abuse field and in research on attention deficit disorders.
People involved: Bethany Brookshire, graduate student
4) Neurotoxicity of Amphetamines. We are documenting the relative impact of neurotoxic doses of methamphetamine and methylenedioxymethamphetamine (MDMA, or ecstasy) on the dopamine and serotonin systems of mice. Along with this project, the identity of the monoamine released by electrical stimulation and detected with carbon-fiber voltammetry electrodes in the ventral tegmental area and the substantia nigra pars reticulata were compared. It was determined that predominantly dopamine is released in the VTA and predominantly serotonin is released in the SNr. In addition, we have investigated the nature of dopamine release in the VTA and found that it is vesicular rather than transporter-mediated.
People involved: Carrie John, Jason Locke